• 中国科学引文数据库(CSCD)核心期刊
  • 中文核心期刊中文科技核心期刊
  • Scopus RCCSE中国权威学术期刊
  • 美国EBSCO数据库 俄罗斯《文摘杂志》
  • 《日本科学技术振兴机构数据库(中国)》
二维码

隧道建设(中英文) ›› 2024, Vol. 44 ›› Issue (3): 515-525.DOI: 10.3973/j.issn.2096-4498.2024.03.009

• 研究与探索 • 上一篇    下一篇

浅埋超大跨隧道出口偏压段双层初期支护承载特征研究

刘夏冰1, 2, 贺少辉3, *, 麻建飞3, 于娅娜1, 2, 郭佳城1, 2, 张军4   

  1. (1. 广东省隧道工程安全与应急保障技术及装备企业重点实验室, 广东 广州 510420;2. 广东华路交通科技有限公司, 广东 广州 510420; 3. 北京交通大学土木建筑工程学院, 北京 100044;4. 中铁大桥局集团第四工程有限公司, 江苏 南京 210031)

  • 出版日期:2024-03-20 发布日期:2024-04-28
  • 作者简介:刘夏冰(1989—),男,江西莲花人,2022年毕业于北京交通大学,土木工程专业,博士,工程师,现从事隧道工程咨询与科研工作。 Email: 627665303@qq.com。*通信作者: 贺少辉, Email: heshaohui1114@163.com。

LoadBearing Characteristics of a Double-Layer Primary Support in Asymmetrically-Pressurized Entrance Section of a Tunnel With Shallow Cover and Super-Large Span

LIU Xiabing1, 2, HE Shaohui3, *, MA Jianfei3, YU Yana1, 2, GUO Jiacheng1, 2, ZHANG Jun4   

  1. (1. Guangdong Provincial Key Laboratory of Tunnel Safety and Emergency Support Technology & Equipment, Guangzhou 510420, Guangdong, China; 2. Guangdong Hualu Transport Technology Co., Ltd., Guangzhou 510420, Guangdong, China; 3. School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China; 4. The 4th Engineering Co., Ltd. of MBEC, Nanjing 210031, Jiangsu, China)

  • Online:2024-03-20 Published:2024-04-28

摘要:

为研究双层初期支护在开挖跨度达26.3 m、拱顶覆土约10.6 m的下北山2号浅埋超大跨4线隧道出口偏压段的工程应用效果,采用数值模拟方法比较单层初期支护和双层初期支护方案的承载特征差异,采用现场实测方法研究出口偏压段双层初期支护的受力特征。研究结果表明: 1)浅埋超大跨隧道在偏压侧的右拱脚~右拱肩范围内支护结构受力偏大,存在局部应力集中,采用双层初期支护技术时的结构承载安全性和对围岩拱顶沉降的控制效果均优于单层初期支护技术; 2)出口偏压段的实测水平收敛最大值为18.5 mm,荷载偏压侧的围岩沉降值达49.5 mm,二次支护施作后在拆撑施工阶段能有效稳定围岩变形; 3)由双层初期支护受力的实测结果可知,传递到二次支护上的接触压力与对应位置围岩/一次支护接触压力之比为16%~33%,荷载偏压侧的右拱脚及右拱肩位置的二次支护轴力约为一次支护轴力的15%,通过二次支护的施作补强了一次支护对偏压侧的承载作用,采用双层初期支护技术提高了浅埋超大跨隧道出口偏压段支护结构的安全储备。

关键词: 浅埋超大跨隧道, 出口偏压段, 双层初期支护, 承载特征, 数值模拟, 现场实测

Abstract: In the construction of the Xiabeishan No.2 tunnel featuring a shallow cover depth of 10.6 m and an impressively wide span of 26.3 m, a novel approach is adopted to enhance its structural integrity. Specifically, a doublelayer primary support system is implemented in the entrance section where the tunnel experiences asymmetric pressure. The effectiveness of singleversus doublelayer primary supports is investigated through numerical simulations. Furthermore, the performance of the doublelayer primary support is examined in realworld conditions via field measurements. The following results are obtained in this study: (1) In the area stretching from the right arch foot to right arch shoulder on the side facing asymmetric pressure, the support structure undergoes substantial stress, with remarkable local stress concentrations. Here, the doublelayer primary support system offers enhanced loadbearing safety and has more effective control over crown deformation than its singlelayer counterpart. (2) Field measurements indicate that the maximum horizontal convergence of the asymmetricallypressurized entrance reaches 18.5 mm. Additionally, the settlement of the surrounding rock at the crown on the pressurized side measures 49.5 mm. These findings suggest that secondary support plays a critical role in stabilizing the deformation of the surrounding rock during the dismantling stage of the primary support. (3) The contact pressure transmitted to the secondary support accounts for 16%33% of the total at the respective locations. Moreover, the axial force exerted on the secondary support at the right arch foot and shoulder on the asymmetricallypressurized side is 15% of that on the primary support. This underscores the vital role of secondary support in enhancing the loadbearing capacity of the primary support under asymmetricallypressurized conditions. In conclusion, the adoption of doublelayer primary support technology substantially improves the structural safety of the entrance section in the Xiabeishan No. 2 tunnel, which faces asymmetric pressure owing to its shallow cover and wide span.

Key words:  , shallow superlargespan tunnel, asymmetricallypressurized entrance, doublelayer primary support, loadbearing characteristic, numerical simulation, field monitoring